Evaluation and Analysis of III-V ESH Processing … and Analysis of III-V ESH Processing Hazards...

Evaluation and Analysis of III-V ESH Processing Hazards

SESHA Hill Country Chapter

December 8, 2011

Brett Jay Davis, PE Zephyr Environmental Corporation

I. Project Background II. SVTC Process Engineers Mini-Survey

Results III. Texas State University Epi Process Tool

Sample Set-Up and Analytical Results IV. SVTC Process Tools Sample Set-Up and

Analytical Results V. Arsenic Wastewater Treatment Technologies VI. Findings and Recommendations VII. Future Work VIII. Acknowledgements IX. Questions?

Presentation Outline

I. Project Background

• Compound (traditional Periodic Table Groups III-V) semiconductor films are being deposited on silicon dioxide wafers, at Texas State Univ. (TSU) in San Marcos, Texas, with further processing at SVTC in Austin, Texas.

• Compound semiconductor processing utilizes a variety of III-V chemicals, such as arsenic, which have potentially unique ESH hazards.

• Little work has been performed to understand the hazards posed by process materials, by-products, effluents and emissions from these processes.

• To better understand the potential personnel and environmental exposures from III-V layering and processing, a detailed evaluation of processing operations was performed at TSU and SVTC, by Zephyr.

Project Background

Periodic Table of the Elements

Period

Group

1 IA 1A

18

VIIIA 8A

1 1 H

1.008

2 IIA 2A

13

IIIA 3A

14 IVA 4A

15 VA 5A

16 VIA 6A

17 VIIA 7A

2 He 4.003

2 3

Li 6.941

4 Be 9.012

5 B

10.81

6 C

12.01

7 N

14.01

8 O

16.00

9 F

19.00

10 Ne 20.18

3 11

Na 22.99

12 Mg 24.31

3 IIIB 3B

4 IVB 4B

5 VB 5B

6 VIB 6B

7 VIIB 7B

8 9 10 11 IB 1B

12 IIB 2B

13 Al 26.98

14 Si

28.09

15 P

30.97

16 S

32.07

17 Cl

35.45

18 Ar 39.95

------- VIII -------

------- 8 -------

4 19 K

39.10

20 Ca 40.08

21 Sc 44.96

22 Ti

47.88

23 V

50.94

24 Cr 52.00

25 Mn 54.94

26 Fe 55.85

27 Co 58.93

28 Ni 58.69

29 Cu 63.55

30 Zn 65.39

31 Ga 69.72

32 Ge 72.64

33 As 74.92

34 Se 78.96

35 Br 79.90

36 Kr 83.79

5 37

Rb 85.47

38 Sr

87.62

39 Y

88.91

40 Zr

91.22

41 Nb 92.91

42 Mo 95.94

43 Tc (98)

44 Ru 101.1

45 Rh 102.9

46 Pd 106.4

47 Ag 107.9

48 Cd 112.4

49 In

114.8

50 Sn 118.7

51 Sb 121.8

52 Te 127.6

53 I

126.9

54 Xe 131.3

6 55 Cs 132.9

56 Ba 137.3

* 72 Hf 178.5

73 Ta 180.9

74 W

183.9

75 Re 186.2

76 Os 190.2

77 Ir

192.2

78 Pt

195.1

79 Au 197.0

80 Hg 200.5

81 Tl

204.4

82 Pb 207.2

83 Bi

209.0

84 Po (209)

85 At (210)

86 Rn (222)

7 87 Fr

(223)

88 Ra (226)

** 104 Rf (261)

105 Db (262)

106 Sg (266)

107 Bh (264)

108 Hs (277)

109 Mt (268)

110 Ds (271)

111 Rg (272)

112 Cn (285)

113 Uut (286)

114 Uuq (289)

115 Uup (289)

116 Uuh (291)

117 Uus (294)

118 Uuo (294)

Lanthanide Series*

57 La 138.9

58 Ce 140.1

59 Pr

140.9

60 Nd 144.2

61 Pm (145)

62 Sm 150.4

63 Eu 152.0

64 Gd 157.2

65 Tb 158.9

66 Dy 162.5

67 Ho 164.9

68 Er

167.3

69 Tm 168.9

70 Yb 173.0

71 Lu 175.0

Actinide Series**

89 Ac (227)

90 Th 232

91 Pa 231

92 U 238

93 Np (237)

94 Pu (242)

95 Am (243)

96 Cm (247)

97 Bk (247)

98 Cf (251)

99 Es (252)

100 Fm (257)

101 Md (258)

102 No (259)

103 Lr (262)

II. SVTC Process Engineers Mini-Survey Results

III-V Process Risks Mini-Survey A. III-V Process Chemistries and By-Products

For the tools that you are familiar with, please complete the following table related to process

chemicals and suspected by-products and residues, during III-V processing only, i.e., normal processing and invasive tasks (such as troubleshooting, daily PMs and major PMs, but not “end of life” tool, infrastructure and process issues).

This information is needed to identify unique III-V process chemicals used and by-products

formed. The knowledge will inform the industrial hygiene and environmental sampling and analyses to be conducted for this project.

Process Type Tool ID Process Chemicals Suspected By - Products and Residues Engineer

(List all chemical inputs) (List all known by - products from chemical - wafer or equipment - wafer interactions)

Dry Etch - Dep CVD08 NH3, NF3, CF4 , N2O, C2F6, SiH4, PH3, N2, O3, He, O2, Ar, 3Ms (trimethyl silane)

Putting on layer of oxide/nitride. No concern Sidi

Dry Etch – PVD MTL06 N2, O2, Ar Min im al : sputtering may dislodge As /Sb Ed Dry Etch PET28BM Cl2, HBr , CH F3, CF4 , NF3, O2, He, O2, CO,

BC L3, N2, Ar (red used by III - V) As /S b containing by product gas, pumped out by system ; minutes in chamber

Gabe

Wet Etch WTS 07/8 HF, HCL, H2SO4, BOE, NH4OH As/Sb particles in che m i cal waste Mark Wet Etch WTS92 HF, HNO3 Back side clean, minim al waste Ray Wet Etch WTC04 H2O2, NH4OH, HCL, H2SO4, HF As/Sb particles in che m i cal waste Mark Deposition – ALD

ALD02PM1 Ar, O2, NH3, O3 Putting additional films . At high temp might be o ut - gassing As /Sb . Minutes to hours in chamber

Sidi

Deposition – ALD

ALD02PM2 A r, O3 Depositing oxide/nitride . No concern Sidi

Deposition – ALD

ALD02PM3 Ar, NH3, O3 Depositing oxide/nitride. No concern Sidi

CMP PLN93 H2O2, slurry, H2O As, Sb on pads Ed Asher ASH07 H2/N2, CF4, N2, O2 Affects resists, will be seeing some As/Sb John

III-V Process Risks Mini-Survey A. III-V Process Chemistries and By-Products (Continued) Potential Personnel Exposures

For the tools that you are familiar with, please list the materials that workers might possibly be exposed to during normal processing or preventive maintenance, during III-V processing and preventive maintenance after III-V processing. This information is needed to determine where industrial hygiene personnel sampling should be performed.

This information indicated that only As and AsH3 are new to silicon manufacturing and with sufficient toxicity to merit IH-type sampling.

Process Type Tool ID Clean Room Operator During Process Equipment Technician During Preventive Maintenance

(List potential exposure materials) (List potential exposure materials) Dry Etch – CVD CVD08 As , S b (only if a gas leak ) As, S b dust , flaking, broken wafers Dry Etch – PVD MTL06 None expected As, Sb dust, flaking, broken wafers Dry Etch PET28BM As , S b ? ( Other react ion gas? ) As, Sb dust, flaking, broken wafers Wet Etch WTS 07/8 NONE Filter changes, broken lines Wet Etch WTS92 NONE Filter changes, broken lines Wet Etch WTC04 NONE Filter changes, broken lines Deposition – ALD ALD02PM1 As , S b (only if a gas leak) As, Sb dust, flaking, broken wafers Deposition – ALD ALD02PM2 As , S b (only if a gas leak) As, Sb dust, flaking, broken wafers Deposition – ALD ALD02PM3 As , S b (only if a gas leak) As, Sb dust, flaking, broken wafers CMP PLN93 During Pad change out Contamin ated pads, broken wafers Asher ASH07 As, S b (only if a gas leak) As, Sb dust, flaking, broken wafers

III-V Process Risks Mini-Survey B. Likely Environmental Discharges

For the tools that you are familiar with, please complete the following table related to any materials discharged during III-V processing. This information is needed to determine which materials need to be sampled and analyzed.

This information indicated that only As and AsH3 are new to silicon manufacturing and with sufficient toxicity to merit environmental sampling.

Process Type Tool ID Wastewater Waste Wet Etch Acids Exhaust Air Chamber Surfaces (List Potential

Materials or Indicate None)

(List Potential Materials or Indicate None)

(List Potential Materials or Indicate

None)

(List Potential Materials or Indicate

None) Dry Etch – CVD CVD08 NONE NONE NONE NONE Dry Etch – PVD MTL06 NONE NONE As , Sb Dry Etch PET28BM NONE NONE As , Sb Wet Etch WTS 07/8 As , Sb HF, BOE (HF&HCL) , As, Sb NONE NONE Wet Etch WTS92 As, Sb HF, HCL, H2SO4, BOE,

NH4OH , As, Sb NONE NONE

Wet Etch WTC04 As, Sb H2O2, NH4OH, HCL, H2SO4, HF , As, Sb

NONE NONE

Deposition – ALD ALD02PM1 NONE NONE As, Sb Deposition – ALD ALD02PM2 NONE NO NE NONE Deposition – ALD ALD02PM3 NONE NONE NONE CMP PLN93 As, Sb, maybe H2O2, As, Sb maybe NONE As, Pb Asher ASH07 NONE NONE As , Sb

III-V Process Risks Mini-Survey

C. Opportunities for Sampling

For the tools that you are familiar with, please enter the projected timeframe of the next III-V processing and preventive maintenance activities, after III-V processing activity. This information is needed to schedule industrial hygiene sampling.

This information indicated that little maintenance sampling would be possible.

Process Type Tool ID Next III - V Processing Next Preventive Maintenance

(Approximate Date(s )) (Approximate Date(s))

Dry Etch – CVD CVD08 Once a month to once every 2 months

Dry Etch – PVD MTL06 Once a week

Dry Etch PET28BM Never

Wet Etch WTS 07/8 Bath changes approx 1/week

Wet Etch WTS92 Every Wednesday

Wet Etch WTC04 Bath changes ap prox 1/week

Deposition – ALD ALD02PM1 Rarely



CMP PLN93 Toss pads weekly

Asher ASH07 1/year

III. Texas State University Epi Process Tool Sample Set-Up and Analytical Results

Note: In all cases, for arsine air sampling, a modified NIOSH 6001 method, inclusive of a pre-filter, was used and for arsenic air sampling, a modified NIOSH 7300 method was used. For arsenic surface sampling, the NIOSH 9100 method was used.

Epi Tool at Texas State University

Back of tool showing pumps collecting from exhaust and near back of reactor

Close up of exhaust sample system

Exhaust Sample System

Filter cassette for arsenic = Modified NIOSH 7300 Method

Sampling pumps – High flow for arsenic, low flow for arsine

Sorbent tube for arsine – Note filter cassette pre-filter = Modified NIOSH 6001 Method

Inside load lock - wipe collected from bottom

Load lock chamber lid – wipe collected from botton

Epi Tool at Texas State University

Epi Tool Analytical Results

* Wipes are typically for 100 cm2 of surface. Action level typically 50 ug. BDL <0.11 ug for Arsine and <0.15 ug for Arsenic in air samples BDL <1 ug for wipes

IV. SVTC Process Tools Sample Set-Up and Analytical Results

Note: The asher and CMP tools were not included in the SVTC processing scheme and therefore were not sampled. Wastewater was not sampled as drain lines at SVTC did not have existing sampling ports. The wet etch tool WTS07/08 was replaced by the wet hood WTS91.

PET28 Front samples

Dry Etch Tool at SVTC

Dry Etch Tool Analytical Results

BDL <0.11 ug for Arsine and <0.15 ug for Arsenic

17

WTS92 Front

First Wet Etch Tool at SVTC

First Wet Etch Tool Analytical Results


WTC04 Front Sample System 2

WTC04 Front Sample System

Chemicals in use: hydrochloric acid, ammonium hydroxide

Wet Clean Tool at SVTC

Wet Clean Tool Analytical Results


ALD02 Exhaust Sample System 2

ALD02 Front Sample System

Chemicals in use: ozone, trimethyl aluminum and argon

Deposition Tool at SVTC

ALD02 Exhaust Sample System ALD02 Back Sample System

Deposition Tool at SVTC

Deposition Tool Analytical Results


CVD08 Front Sample System

Chemicals in use: TEOS and oxygen

Chemical Vapor Deposition Tool at SVTC

BDL <0.11 ug for Arsine and< 0.15 ug for Arsenic

Chemical Vapor Deposition Tool at SVTC

WTS91 Front

WTS91 Spin Rise Dryer Sample System

Chemicals in use: dilute phosphoric acid and hydrogen peroxide

Second Wet Etch Tool at SVTC

Second Wet Etch Tool Analytical Results

BDL <0.11 ug for Arsine and< 0.15 ug for Arsenic (in air) and <1 mg/Kg (in liquid)

MTL06 Maintenance Sample System

MTL06 Maintenance Sample System

Metal sources in use: molybdenum, ruthenium, tungsten, hafnium

Metal Deposition Tool at SVTC

MTL06 Open Maintenance Sample System

MTL06 Target Maintenance Sample System


MTL06 Wafer Stand Wipe

MTL06 Target Perimeter Wipe

Chemicals in use: argon and nitrogen


Metal Deposition Tool Analytical Results

BDL <0.11 ug for Arsine and < 0.15 ug for Arsenic for air samples BDL <1 ug for wipes

Sampling Results Summary

• Except for the MBE tool load lock, no arsenic or arsine was detected at above analytical detection method limits. – Note: Due to the short process and

sampling durations, this information cannot be correlated with personnel exposure limits, which are typically defined as average exposures over eight-hours.

• ACGIH TLV-TWA = 0.005 ppm ASH3

• ACGIH TLV-TWA = 0.01 mg/m3 As

V. Arsenic Wastewater Treatment Technologies

Arsenic Contaminated Wastewater Treatment Technologies

• In early 2011, Zephyr was retained by ISMI to perform an assessment of available arsenic removal technologies.

• The purpose of the project was to provide guidance on the possible treatment of arsenic from the application and processing of compound (III-V) semiconductor films on silicon oxide substrates, as presently being demonstrated at SVTC in Austin, Texas.

• The resulting table of available technologies and their capabilities and limitations follows.

Arsenic Contaminated Wastewater Treatment Technologies

Arsenic Contaminated Wastewater Treatment Technologies (continued)

VI. Findings and Recommendations

Findings and Recommendations

As expected: • Dry semiconductor processing of silicon wafers with gallium

arsenide films, did not liberate arsenic or arsine into the workspace (at least not above detection limits).

• Wet semiconductor processing of silicon wafers with gallium arsenide films, did not liberate arsenic or arsine into the workspace or into an acid bath (at least not above detection limits).

This project did not detect EHS hazards that would require additional personnel protection or environmental controls, however: • It is advisable to perform personnel monitoring for III-V

processing at a production facility, preferably with lower method detection limits than those available for this project.

VII. Possible Future Work

Future Work

• Investigate ability to obtain lower detection limits – Portable FTIR? • Perform wipe sample on load lock before and after processing • Sample for off-gassing from wafer box • Sample during maintenance of all wet and dry tools • Sample wastewater discharged from wet etch and CMP processing • Sample metal deposition tool exhaust • Analyze waste wafers for TCLP concentrations • Investigate need to repeat project for other Group V semiconductor

compounds, such as antimony and bismuth

VIII. Acknowledgements

Acknowledgements

This project was successful thanks to the following people:

• The Banker – Steve Trammell, ISMI • The Architects – Niti Goel, Wei-E Wang and Kevin Wolfe,

Intel • The Superintendent – Bob Bianconi, SVTC • The Foremen – Barry Sassman and Melvin Cruz, ISMI • The Builders – Tiffany Giles and Jeanne Yturri, Zephyr • The Inspectors – Sara Brenner and Hallie Morgan, CNSE,

and Galson Laboratories

IX. Questions?

Thank you!

Brett Jay Davis, PE

Zephyr Environmental Corporation

[email protected]

Phone: 512-879-6628

Visit us at www.ZephyrEnv.com and www.HazMatAcademy.com

Evaluation and Analysis of III-V ESH Processing … and Analysis of III-V ESH Processing Hazards...

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Transcript of Evaluation and Analysis of III-V ESH Processing … and Analysis of III-V ESH Processing Hazards...